Russia’s communications watchdog accused Twitter on Tuesday of deleting banned content too slowly in the latest dispute between a major government and Big Tech.

Axar.az reports that Moscow said earlier this month it had slowed the speed of U.S.-based Twitter inside Russia and on March 16 threatened to ban the social media service outright in a month over content from child pornography to drug abuse.

With Twitter widely used in Russia by government opponents, including Kremlin critic Alexei Navalny and his allies, Twitter said at the time it was worried about free speech and denied that it let its platform be used to promote illegal behaviour.

The watchdog, Roskomnadzor, said in a statement that Twitter was too slow in tackling illegal posts.

“The rate at which the social network is removing banned information is unsatisfactory,” it said. “Two thirds of material that is harmful for children remains available on Twitter.”